Shelf



FIG. 1 is a perspective view of a shelf showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof; and,

FIG. 4 is an end view thereof, the opposite end being a mirror image of the end shown.

The shelf is shown broken-away in the views to indicate indeterminate length. 

The ornamental design for a shelf, as shown and described. 